Therapeutic and diagnostic algorithm for preoperative prediction of sporadic multigland parathyroid disease

Abstract

BACKGROUND: Primary hyperparathyroidism (PHPT) is a common endocrinological disease that is characterized by autonomic increased synthesis of parathyroid hormone (PTH) with elevated or upper-normal levels of blood calcium [1]. In 80–85% of cases, the cause of sporadic PHPT is an adenoma of one parathyroid gland (PTG) (sigle-gland parathyroid disease), in 20–25% — a lesion of a larger number of PTGs (hyperplasia of all glands or double adenomas — multigland parathyroid disease) [2]. The complexity of clinical and laboratory prediction, low sensitivity of imaging methods, poor assessment of the radicalness of the operation by intraoperative monitoring of intact PTH (IMiPTH) are the components of the problem of multiple lesions in PHPT. Therefore, the improvement of existing and the development of new methods for diagnosing and treating this variant of the disease are urgent tasks of modern endocrine surgery.AIM: To develop an algorithm for the diagnosis and treatment of PHPT, aimed at preoperative detection of multigland parathyroid disease.MATERIALS AND METHODS: The study was based on a study of a continuous sample of 208 patients, of which 34 with multigland parathyroid disease in PHPT, 95 with single-gland parathyroid disease in PHPT, 69 with secondary hyperparathyroidism on renal replacement therapy (RRT) with hemodialysis, and 10 with tertiary hyperparathyroidism on RRT of LT. The work was performed on the basis of clinical, laboratory, instrumental, morphological and immunohistochemical studies. The nature of the expression of the calcium-sensitive receptor and the vitamin D receptor in the studied groups was studied as a pathogenetic substantiation of the proposed algorithm [3]. Based on the study of clinical and laboratory parameters and the results of preoperative imaging methods, predictors of multigland parathyroid disease in PHPT [4,5] were established, and a method for differential diagnosis of PTG lesions in PHPT was developed [6]. In addition, the results of surgical treatment of patients with multiple PTG lesions in various clinical variants of hyperparathyroidism were studied [7]. RESULTS: The proposed algorithm is used when the diagnosis of PHPT is already established and there are indications for surgical treatment. First of all, the level of GFR (CKD-EPI) is assessed in conjunction with the results of the “gold standard” preoperative imaging methods (ultrasound and scintigraphy), with an assessment of the number of localized increased PTG and the consistency of the results of preoperative methods.At a GFR level of more than 73 ml/min/1.73 m2, an increase of only 1 PTG according to the results of 2 imaging methods, provided that they are consistent, the PHPT variant is defined as a sigle-gland parathyroid disease. If there is an inconsistency between the 2 methods of preoperative imaging, we recommend calculating the scores according to the differential diagnosis scale for multiple lesions in PHPT [6]. At a GFR level of less than 73 ml/min/1.73 m2, an increase of >1 PTG according to the results of 2 imaging methods, we recommend calculating points according to the proposed scale [6].With the established variant of PHPT — sigle-gland parathyroid disease, the patient undergoes selective parathyroidectomy (PTE) with IMiPTH. When iPTH drops to reference values, the test is considered positive, and the operation ends there. If the test result is negative, a second test is required after 10 minutes. In the event that the repeated test is also negative, then the patient is shown a bilateral neck exploration (BNE) in accordance with the tactics for multigland parathyroid disease (see below).With the established variant of PHPT — multigland parathyroid disease, the following tactics are used:BNE with obligatory exploration of all four PTGs;Macroscopic assessment of the PTG found.When making a decision about 2 pathologically changed enlarged PTG, and 2 others are intact and not enlarged, a double PTE with IMiPTH is performed. If after the removal of 2 pathologically altered PTGs, the IMiPTH test is negative, then a second one is necessary after 10 minutes. In the event that the repeated test is negative, then from the 2 recognized intact ones, the least altered is determined and the scope of the operation is expanded to subtotal PTE (3.5 PTG), leaving ½ of the least altered PTG. The operation ends here.When deciding that 3 or more PTG are pathologically changed and enlarged, a subtotal PTE with IMiPTH is performed. In case of a negative IMiPTH test, the places of possible ectopic location of the PTG are examined: thyrothymic ligaments, upper thymus horns, fatty tissue along the carotid arteries. If there are no ectopically located PTGs in the indicated places, the operation is completed.CONCLUSION: The proposed treatment and diagnostic algorithm is pathogenetically substantiated, aimed at preoperative detection of multiple PTG lesions in PHPT and will improve the quality of life of this group of patients by reducing the persistence of the disease.